Suspension is the name given to the system of springs, shock absorbers and linkages that connects a vehicle to its wheels. Suspension systems serve multiple purposes including contributing to the vehicle's road holding/handling and braking for good active safety and driving pleasure as well as keeping vehicle's user(s) comfortable and reasonably well isolated from road noise, bumps, and vibrations, etc. These goals are generally at odds with one another, so the tuning of suspensions involves finding the right compromise. It is important for the suspension to keep the road wheel in contact with the road surface as much as possible, because all the forces acting on the vehicle do so through the contact patches of the tires. However, reducing the interaction between the vehicle and road surface improves the ride comfort for the user(s). Even for one class of vehicle, such as a car, there may be different balances in this compromise as a driver of a sports car wishes to have a different “feel” for the ride than say a driver of a family sedan or estate wagon with their family.
Further, the springs, shock absorbers and linkages will be designed differently even for a single vehicle model, such as for example a BMW 5-series, where it is offered as a conventional 4-door saloon and as a 5-door estate providing increased rear luggage/storage space and hence be designed for substantially heavier loading at the rear than the saloon. The design of front and rear suspensions of cars, trucks, all-terrain vehicles (ATVs), motorcycles are generally different and can vary further with each manufacturer and model. However, at their core they all function in essentially the same manner.
Across all vehicle types and suspension designs there is generally a common element within all of them, a single rear coil-over-shock system attached between the vehicle frame and wheel. Accordingly, for the entire complex mechanical system that is the suspension the constraints between comfort and wheel contact are now coupled through this single coil-over-shock system. The shock, also known as a shock absorber, dampens the vertical motion induced by the vehicle travelling across a rough surface and so should technically be referred to by their ‘proper’ name—dampers. If the vehicle only had springs forming the suspension then whilst vertical motion would be absorbed the vehicle would “boat and wallow” or “rock and roll” along the road surface road making the user physically sick at the least or crashing through the poor control they had of the vehicle. Either that or the incessant vibration would cause it to fall apart.
The shock performs two functions. Firstly, they absorb any larger-than-average bumps in the road so that the upward velocity of the wheel over the bump isn't transmitted to the vehicle chassis. Secondly, they keep the suspension at as full a travel as possible for the given road conditions so that the wheel is in contact with the road surface. However, by also being velocity-sensitive hydraulic damping systems the faster they move, the more resistance there is to that movement, and so their behaviour is different for slow variations in the road surface to rapid variations. They also work in conjunction with the springs which allow the movement of the wheel and allow the energy in the road shock to be transformed into kinetic energy of the unsprung mass, whereupon it is dissipated by the shock. The shock does this, typically, by forcing gas or oil through a constriction valve. Adjustable shock absorbers allow you to change the size of this constriction, and thus control the rate of damping.
Accordingly, it would be beneficial to provide a suspension that was based in some embodiments upon a dual-shock system wherein the two shocks were in opposite states so that even under absorption of the vertical shock from the road surface there was still applied additional force for road contact to be maintained. It can also be shown to be beneficial in single-shock systems to place the shock the opposite side of the fulcrum point of the suspension system, counter to previous prior art solutions.